I am worried, I had white sports bras that being a discoloured grey, i dyed black with idye poly. They are 80%polymide and 20%elastane. they have turned out perfect so far (still damp and drying) Very deep black even the plastic hooks and eyes are black!!

however, when rinsing, initially the water began to run clear, but the second I added non bio detergent, the colour seeped out like blood until i started to rinse again in clean water by which point it started to run clear again...?

My worry is, these sports bras are to be worn under white karate suits, and training is intense, so will this dye run into my white suite when sweating?

Is there anyway to set the colour in these bras?

I've followed the instructions perfectly so far; added dye & colour enhancer, boiled for an hour then rinsed in warm then cold water and then added detergent. rinsed again, spun and is now drying.